At Tuesday's town planning committee meeting we had one applicant for a parking waiver. He made a quick presentation showing how they planned to add another office space to a warehouse and add a couple parking places for it. This just involved putting marks on the warehouse driveway. It doesn't require a zoning change. It's just a change to the registered building plan.
The chair asked the consulting engineer for his report. He listed changes A, B, C, ... and G between the plans he was given and the new plan. Two board promptly started talking about changes B and C. They had a bunch of doubts and questions. The applicant answered some questions and dug through his documents.
As the two board members got going he put up another plot plan and asked: "Why are we talking about this again? You agreed to this back in November. See, here are your signatures on the approved plan. It shows those changes."
The consulting engineer said he had been given plans dated July for comparison. A quick look and he agreed that the only change between the signed November plan and the proposed plan was the office space layout and parking places. The two board members walked up, saw their signatures, and sat back down.
The office space and parking change was agreed to be minor and the new plans approved.
Signatures exist in large part to make board members and applicants shut up and sit down.
This works for several reasons.
First, there is a signing ceremony. This ceremony involves ritual motions, ritual words, public observation, and sometimes other steps. The ceremony is a recognized and understood end point. It ends social acceptance your ability to make changes. It is important that the the ritual motions be unique. A physical signature is a ritual motion that you almost never use for any other purpose. It is not just an emotional or intellectual difference. The physical movements are unique, non-trivial, and not accidental. You must use muscles and eyes to perform it properly. It leaves behind a physical artifact that you personally recognize.
Similarly, the witnesses are physically there and can observe and confirm this ritual motion. After a while, they also have the ability to immediately recognize the resulting physical artifact.
For plot plans there is more to the ritual. Not only are there the signatures of the board, this is preceded by stamping the plot pages with the official stamp, the signatures are on the stamp, and after the signatures are there the paper is sealed with a press that bends, dents, and selectively tears the paper that was stamped. All of this is something that can be recognized and confirmed by those present.
Second, the board members immediately recognized the physical results of that ceremony and recognized the social power. They shut up. This was not some arguable computer magic. They were able to perform their own immediate verification.
Perhaps some day the digital signature will reach the level that these physical signatures have reached. There will be the ceremony that ensures that all the participants recognize that they are agreeing to an endpoint. Pushing a button on a computer is not a unique ceremony with witnesses. It is not a unique motion used for no other purpose. A whole ceremony process needs to be invented for the digital signature that it presently lacks.
Issues of ceremony, social witnessing, etc. are malleable. Ceremonies change. So the digital signature can reach general acceptance, but the endless fascination with esoteric internal implementation details is not creating a proper ceremonial process. In fact, the current user interfaces for computers make it quite a large challenge to create a proper family of ceremonies. Physical signature ceremonies are rather adaptable and cover the range from the quick initialling in a hurry to the formal multiparty signing ceremony with stamps and seals that is used for building plan approvals. Digital signing ceremonies will need to provide that same spectrum of ceremony.
The validation of signatures is similarly immature. There is no technological barrier to the quick verification of physical signatures. Those two board members took less than a second to confirm their own signatures. They could have argued forgery. Forgery is unlikely because of the high cost of creating the forgery and the near certainty that it would be discovered because other duplicate copies of the plans are kept in storage at various locations. A successful forgery would need to substitute those also. Getting approval for an office and some parking does not justify all that expense and risk.
Digital verification might reach that same degree of universality some day, but it will take decades or centuries. It's not just a matter of computer access. What the board members were verifying was that the plans that they saw had been signed. If a computer were involved you must figure out how to ensure that the photons emitted correspond to the digital signatures. The relationship between photons and signatures is inherent in the physical processes of paper and light. If this were a plan being projected by a computer, how do I know that the digital signature corresponds to the projection? If I do not trust the presenter, why trust the projection. This means that I need the document to be provided to me so that I can use a computer and projection system that I trust. Lack of trust can go both ways, so this comparison of photons can become very difficult logistically. Every participant must have their own trusted viewing system and verification system. It's a rather huge investment in equipment and facilities to reach the point where everyone has this and can confirm signatures to their own satisfaction in less than a second.
For now, that piece of paper and those physical signatures are meeting the signature goal. The investment in physical resources and new scial ceremonies will not happen just to improve signatures. The improvement is not that valuable. It will happen when other reasons and purposes have justified the investment in computers, etc. Then social ceremonies can be created and digital signatures finally become practical. (Assuming that something better has not been invented first.)